From 4617721c502b2ddaa4e324e86da4997edf738fa5 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Wed, 2 Sep 2026 09:55:01 -0400 Subject: ftrace: Synchronize the initialization of ftrace_ops There's some internal state that ftrace_ops needs to have set, but since it can be declared outside of the ftrace.c code, it calls ftrace_ops_init() on the ops in every global function. The issue is that if two tasks call it on the same ops at the same time it is possible to have the initialization of one corrupt the initialization of the other call. Create a ops_mutex to use to synchronize every initialization of the ftrace_ops. The mutex is taken within checking the ftrace_ops flag that states it was initializied but the flag is checked again after the mutex has been taken. Checking first outside the mutex allows it to shortcut having to take the mutex. But then the check needs to be done again after the mute is taken in case of races. Cc: stable@vger.kernel.org Link: https://patch.msgid.link/20260902095501.6b59af20@gandalf.local.home Fixes: f04f24fb7e48d ("ftrace, kprobes: Fix a deadlock on ftrace_regex_lock") Reported-by: sashiko-bot@kernel.org Close: https://lore.kernel.org/all/20260829025528.49A831F000E9@smtp.kernel.org/ Signed-off-by: Steven Rostedt --- include/drm/drm_module.h | 125 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 125 insertions(+) create mode 100644 include/drm/drm_module.h (limited to 'include/drm/drm_module.h') diff --git a/include/drm/drm_module.h b/include/drm/drm_module.h new file mode 100644 index 000000000..4db1ae03d --- /dev/null +++ b/include/drm/drm_module.h @@ -0,0 +1,125 @@ +/* SPDX-License-Identifier: MIT */ + +#ifndef DRM_MODULE_H +#define DRM_MODULE_H + +#include +#include + +#include + +/** + * DOC: overview + * + * This library provides helpers registering DRM drivers during module + * initialization and shutdown. The provided helpers act like bus-specific + * module helpers, such as module_pci_driver(), but respect additional + * parameters that control DRM driver registration. + * + * Below is an example of initializing a DRM driver for a device on the + * PCI bus. + * + * .. code-block:: c + * + * struct pci_driver my_pci_drv = { + * }; + * + * drm_module_pci_driver(my_pci_drv); + * + * The generated code will test if DRM drivers are enabled and register + * the PCI driver my_pci_drv. For more complex module initialization, you + * can still use module_init() and module_exit() in your driver. + */ + +/* + * PCI drivers + */ + +static inline int __init drm_pci_register_driver(struct pci_driver *pci_drv) +{ + if (drm_firmware_drivers_only()) + return -ENODEV; + + return pci_register_driver(pci_drv); +} + +/** + * drm_module_pci_driver - Register a DRM driver for PCI-based devices + * @__pci_drv: the PCI driver structure + * + * Registers a DRM driver for devices on the PCI bus. The helper + * macro behaves like module_pci_driver() but tests the state of + * drm_firmware_drivers_only(). For more complex module initialization, + * use module_init() and module_exit() directly. + * + * Each module may only use this macro once. Calling it replaces + * module_init() and module_exit(). + */ +#define drm_module_pci_driver(__pci_drv) \ + module_driver(__pci_drv, drm_pci_register_driver, pci_unregister_driver) + +static inline int __init +drm_pci_register_driver_if_modeset(struct pci_driver *pci_drv, int modeset) +{ + if (drm_firmware_drivers_only() && modeset == -1) + return -ENODEV; + if (modeset == 0) + return -ENODEV; + + return pci_register_driver(pci_drv); +} + +static inline void __exit +drm_pci_unregister_driver_if_modeset(struct pci_driver *pci_drv, int modeset) +{ + pci_unregister_driver(pci_drv); +} + +/** + * drm_module_pci_driver_if_modeset - Register a DRM driver for PCI-based devices + * @__pci_drv: the PCI driver structure + * @__modeset: an additional parameter that disables the driver + * + * This macro is deprecated and only provided for existing drivers. For + * new drivers, use drm_module_pci_driver(). + * + * Registers a DRM driver for devices on the PCI bus. The helper macro + * behaves like drm_module_pci_driver() with an additional driver-specific + * flag. If __modeset is 0, the driver has been disabled, if __modeset is + * -1 the driver state depends on the global DRM state. For all other + * values, the PCI driver has been enabled. The default should be -1. + */ +#define drm_module_pci_driver_if_modeset(__pci_drv, __modeset) \ + module_driver(__pci_drv, drm_pci_register_driver_if_modeset, \ + drm_pci_unregister_driver_if_modeset, __modeset) + +/* + * Platform drivers + */ + +static inline int __init +drm_platform_driver_register(struct platform_driver *platform_drv) +{ + if (drm_firmware_drivers_only()) + return -ENODEV; + + return platform_driver_register(platform_drv); +} + +/** + * drm_module_platform_driver - Register a DRM driver for platform devices + * @__platform_drv: the platform driver structure + * + * Registers a DRM driver for devices on the platform bus. The helper + * macro behaves like module_platform_driver() but tests the state of + * drm_firmware_drivers_only(). For more complex module initialization, + * use module_init() and module_exit() directly. + * + * Each module may only use this macro once. Calling it replaces + * module_init() and module_exit(). + */ +#define drm_module_platform_driver(__platform_drv) \ + module_driver(__platform_drv, drm_platform_driver_register, \ + platform_driver_unregister) + +#endif -- cgit v1.3.1